A mother involved in a contentious custody case has been charged with killing her 13-year-old autistic son and 9-year-old daughter in California after a judge ordered them returned to their father in Georgia.

Authorities weren't releasing many details, but one of the special circumstances filed by prosecutors against 42-year-old Marilyn Edge alleges the children were poisoned.

Edge, of Scottsdale, Ariz., is scheduled to be arraigned Tuesday. She was charged Monday with two counts of murder with special circumstances in the deaths of her daughter Faith and son Jaelen.

Edge lost custody of them on Wednesday in a Georgia case then texted her ex-husband, Mark Edge, two days later that she would bring the children back on Sunday, his attorney Marian Weeks said.